I’m getting a hum in my integrated tube amp and it’s bugging me alot


Hi - first of all, here’s my system:

- Rogers High Fidelity EHF-200 mkII integrated tube amp

- Magico A5 speakers

- Merging NADAC + Power DAC

- Audience T2 power conditioner

- Purist cabling

I love the sound of my system. BUT…….I have been noticing a hum after about 10 minutes of use from my amp. There are two switches on the amp - POWER & OPERATE - that need to be turned on in order to listen to music. (The Power switch needs to be turned on about 30 seconds prior to switching on the Operate switch). With both KT150 and KT88 tubes (all matched), after about 10 minutes I hear an audible hum from the amp that is apparent from my listening position about 10 feet away. If I turn off the OPERATE switch, the hum disappears (but of course, then I can’t listen to music). I have contacted Roger (the company owner) who said it was noise from old tubes. But my KT88’s have less than 100 hours on them and they hum as well as the KT150’s (maybe a few db’s softer than the 150s’). 

 

Does anybody have any ideas about what causes this and how it might be fixed? Is this an issue that is endemic to tube amps? FYI - if this requires new tubes, then I need to switch back to SS as I’m not willing to invest approx $800/year in new tubes. 

 

I turn to the great wisdom of this forum to help.

 

Thanks - Matt

mwsl

Any hum is not a characteristic of tube amps. Definitely do not give up on tube amps. I have more than 15,000 hours on tube equipment and have had to replace one tube that misbehaved. Typically, you get at least 2 - 3,000 hours between tube changes. The benefit really outweighs the risks.

 

 

It is probably a malfunctioning transformer (@2psyop +1 ) or something else (. Definitely contact Rogue. While I am not a fan of Rogue, they should point you in the right direction.

 

 

Rogers brags about a lifetime guarantee. It seems like he blew you off rather quickly. I would call back as @stereo5 suggested.

Huh? 16000 dollars for this humming junk?! (I just looked it up). Return quickly to botcher Roger and get your money back.

Thereafter, get some smooth liquidy class A solid state Pass Labs to keep that Magico well behaved. 

Not an expert, but you may have some DC on your line. You might try one of these:

https://avahifi.com/products/humdinger-dc-line-blocker

There are other options, this one is fairly inexpensive.